1. Field of the Invention
The present invention relates to a radio access system supporting multi-radio access technology (RAT) and, more particularly, to a method and the apparatus for transmitting and receiving data over two or more heterogeneous networks.
2. Related Art
In a conventional radio communication environment supporting two or more heterogeneous networks, although a terminal has capabilities to access multi-RAT, the terminal is unable to access the multi-RAT at the same time and transmit and receive data to and from the two or more heterogeneous networks at the same time.
That is, a conventional terminal supporting multi-RAT accesses any one RAT based on switching and transmits and receives data over one network. Accordingly, if a terminal having multi-RAT capabilities transmits and receives data over a specific network and transmits and receives data over a network different from the specific network, the transmission and reception of data over any one network is stopped.
Accordingly, in the prior art, a terminal having capabilities supporting two or more heterogeneous networks is able to perform communication by using different networks, but efficiency is limited because the terminal operates based on simple switching.
Furthermore, since different networks independently operate, an inefficient operation is performed from a viewpoint of the overall flow management of a terminal.
For this purpose, methods have been defined for a terminal having multi-RAT capability in which the terminal simultaneously transmits and receives data by using two or more heterogeneous networks (e.g., a first system and a second system), i.e. by transmitting and receiving data through each network simultaneously.
The methods defined above, however, enable the multi-RAT MS to communicate only the data corresponding to specific service flow with the second system through the control by the first system.